There's no hope of getting in the garden today, the wind is wild and the rain is lashing down. I got the side panels cut out and planed down during the week, so today was a scarfing day. I laid the bottom panels out on offcuts of exterior ply covered with polythene sheet and screwed down the new centre section. I then screwed each of the remaining parts of the original bottom panels to each end. I did the same with the side panels, but in this case there is only one join to make.
I also put the sheer clamps back in the scarfing jig I made. On each side there is a long piece of 2x1" (50x25mm) to act as a straight edge and these and the bottom are again covered in polythene. Down the centre is a strip of mdf about the same thickness as the sheer clamps. I use offcuts of the 4mm ply covered in plastic parcel tape to bridge from one sheer clamp piece to be held over to the centre piece of mdf scrap. A screw near the sheer clamp end provides the clamping pressure but still allows a slight amount of adjustment until I'm happy everything is properly aligned.
